This invention relates generally to systems for de-reeling wire from wire-filled spools, and more particularly to arrangements which permit high-speed de-reeling to be achieved.
Applicant's U.S. Pat. No. 3,425,647 dated Feb. 4, 1969 discloses one such wire pay-off arrangement for a spool. In this patented device, wire from the spool was adapted to be payed off one free end, with the spool being held stationary. In order to reduce the tendency for the wire to wear against the flange, there was provided a freely-rotatable wheel or cap at the free end of the spool, having a curved peripheral rim which extended beyond the spool end flange and prevented the unraveling strand from directly contacting the same. The wheel, being essentially free, was capable of rotating at a speed which was commensurate with the speed at which the strand traveled around the periphery of the spool flange. Naturally, as the take-off speed increased, the wheel speed also increased as a result of its frictional engagement with the strand.
In addition, the patented device incorporated a circular brush having radial tines, the tines being stationary and extending a short distance past the peripheral portion of the wheel. As the strand of wire traveled, it brushed by the tines, one or several at a time. With the disclosed arrangement, the number of tines was sufficiently small so that any drag force imparted to the traveling strand was small, particularly at low-take-off speeds. In the event that pay-off was suddenly stopped, the engagement of the strand and the tines prevented undesirable looseness of the wire by inhibiting continued unraveling of those turns of wire remaining on the spool.
While the above arrangement was satisfactory for many installations, several problems appeared when it was desired to increase the speed at which wire was payed off the spool. In particular, with high pay-off speeds, the relatively few numbers of separate tines was, in some cases, insufficient to halt the wire promptly in the event that the take-off speed was suddenly reduced. Increasing the number of tines over that shown in the patented device had a desired effect of increasing the drag force on the individual strand, but created other problems when it was desired to employ such high-speed de-reeling equipment. Where the wire gauge was relatively small, high take-off speeds resulted in considerable drag forces, these sometimes being sufficient to cause breakage of the strand. In applications where the take-off speed approached thousands of feet per minute, sudden breakage of the wire strand caused great problems, with significant accumulation of unraveling turns and the resulting looseness, kinking, etc., which tended to make the entire operation overly complex. The resulting down-time, as well as the loss represented by broken strands, proved unacceptable for many installations. In certain cases, broken strands could be repaired by splicing but in other cases, a broken strand might result in scrapping an entire reel, especially where a splice-free, single length (continuous) of wire was required.
Other efforts involved controlling the speed of the take-off wheel in order to minimize the tendency of the same to continue unraveling wire after the take-up speed was suddenly halted. One solution to this problem was disclosed in applicant's U.S. Pat. No. 3,972,489 dated Aug. 3, 1976. The patented device involved a take-off mechanism incorporating a stationary tension brush, and a rotatable wheel as in the previous patent, with the exception that an adjustable brake mechanism was provided on the wheel such that a consistent drag force opposing the free rotation of the wheel was applied thereto. The magnitude of the force imparted by the brake was set manually by the operator, to suit the particular conditions as dictated by the type of wire being de-reeled, the gauge, take-off speed, etc. This particular arrangement solved a number of problems which were inherent in prior de-reeling mechanisms.
In spite of the advances provided by the two patented devices mentioned above, as well as other new arrangements which have been devised by others and which constitute the prior art as of the present time, problems still remained when it was attempted to achieve high-speed operation involving pay-out of wire from the free end of a spool, where relatively fine, fragile wire was being transferred and where the tensile strength of the wire was not sufficiently high. Fine-gauge copper wire is an example of one of the items which has been found to cause great difficulty. The drag effect of multiple tines which were brushed by the traveling strand often proved to be too great, resulting in breakage. This had the undesirable consequences noted above, resulting in excessive downtime, waste of product, the need for splicing, etc.
Prior fixtures of the type which carried multiple spools and which were intended to permit de-reeling from a series of such spools have been devised. They all suffered from the inability to quickly shift the de-reeling operation to a full spool once a partially filled unit was emptied. Some arrangements required a complete halting of the pay-off operation while the transfer was manually effected. This resulted in unnecessary and costly downtime, with its consequent bother and expense.